Hydraulic flash welder control



May 26, 1953 y K. A. DoUTT 2,640,134

HYDRAULIC FLASH WELDER CONTROL Filed ocr. 12, 195o Y 5 sheets-sheet 1 33 /aa 7g Eyman/t A rra/ENEL May 26, 1953 K. A,.DoUTT HYDRAULIC FLASH WELDER CONTROL 5 sheets-smet 2 Filed OCT.. l2, 1950 May 26, 1953 K. A. DoUTT HYDRAULIC FLASH WELDER CONTROL 5 Sheets-Sheet 5 Filed Oct. l2, 1950 Jl 4111111111 "l "E111- l l I ESSI:

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May 26, 1953 K. AJfDoUTT HYDRAULIC FLASH WELDER CONTROL 5 Sheets-Sheet Filed Ooi. 12, 1950 Rm WN \m -m -nulmm @W Nm May 26, 1953 K. A. noUTT HYDRAULIC FLASH WELDER CONTROL 5 Sheets-Sheet 5 Filed Oct. 12, 1950 Patented May 26, 1953 UNITED STATES PATENT OFFICE HYDRAULIC FLASH WELDER CONTROL Kingsley A. Doutt, Detroit, Mich.

Application October 12, 1950, Serial No. 189,835

8 Claimsu l This invention relates to electric welding apparatus and more particularly to an improved apparatus for imparting controlled movement to the movable platen of a ash welding machine. Flash welding machines as known in the art comprise essentially an insulated normally fixed platen having an electrode and means to secure a workpiece thereto. A movable platen is also provided and includes an electrode and workpiece securing means. The movable platen is arranged for sliding movement toward and away from the fixed platen and means is provided for imparting such movement thereto. In the present disclo` sure at least one hydraulic'cylinder and piston assembly is provided, the piston being connected to the movable platen.

In order that a controlled volume of hydraulic iiuid may be supplied to the piston and cylinder assembly utilized, various types of valves `and p valve controlling means have been heretofore proposed and used. Such devices have generally had in common a mechanical connection with the movable platen of the flash welding machine so that the valves or other devices controlling w and moving the movable platen were in turn controlled by the position of the movable platen itself and/or the speed of travel thereof. Those skilled in the art recognize that such dependency of the controlling elements of a ilash welding machine is subject to variation depending upon the characteristics of the platen and workpiece, etc., to the end that an unequal and often undesirable action follows which results in an unsatisfactory weld.

Those skilled in the art are also aware that an improved welding` technique will result from a desirably controlled and timed flash Welding operation and it is, therefore, a principal object of this invention to provide a hydraulic flash Welder control operating to impart a most desirable welding cycle movement and control to the movable platen of the flash welding machine regardless of variations in the hydraulic pressure utilized,-conditions effecting the movable platen and variations in the workpieces as to size, thickness. material, shape, etc.

A further object of the invention is the provision of a hydraulic ash welding control for a flash welding machine arranged to perform a complete welding cycle from flashing to upsetting with no hesitation in the controlled and timed advance of the movable platen and operating in effect to superimpose upsetting action on a continuing dashing action.

Those skilled in `the art will recognize that flash Welder controls as heretofore known in the art had a common weakness in controlling the motion of the movable platen of the flash welding machine in the welding cycle, particularly in that hesitancy in the forward progressive motion ci the movableplaten frequently resulted in no weld or a poor weld due to instantaneous oxidation of various metals occurring at the time of hesitation or momentary interruption between the dashing and upsetting action in the flash welding machine. The present invention enables a continuous performance cycle and thereby eliminates completely the possibility of no welds or poor welds due to such oxidation.

A still further object of the invention is the provision of an improved apparatus for imparting controlled movement to the movable platen of a iiash Welding machine and which apparatus produces a flashing cycle in accordance with its preset controls and superimposes an upset cycle on the flashing cycle, the movement of the platen during the flashing cycle being responsive only to the apparatus and the upset cycle being responsive to the position of the platen and Workpieces.

A still .further object of the invention is the provision of a control system for a flash Welder as above outlined which facilitates and simpli- -lies the setting up of the welding machine to perform a particular welding operation and the apparatus therefore includes means for readily changing the pattern of movement of the platen during hashing and, in accordance with a preferred embodiment of the invention, the same is accomplished by employing a simple and positive valve actuated control of the apparatus incorporating relatively movable valve members enabling various desired settings to be readily achieved.

A still further object of the invention is the attainment of a wider diversity and greater accuracy in the control 0i the Variables making up a flash welding operation. For example, the pattern of the rate of change of the movable platen during the ilashing action may be readily varied with respect to time and the interval between the initiation oi hashing and the start of the upsetting. Such variable factors enable a much higher degree of control over the welding operation to be achieved and thereby contribute substantially to the quality of the work performed.

A still further object of the invention is the provision oi' a hydraulic welder control which facilitates and simplifies the setting up oi' the Welding machine to perform a particular welding operation especially when the operation is to be repeated under automatic control. The invention, therefore, includes means for `eadily changing the pattern oi movement of the movable platen during the flashing and upsetting portions the welding cycle, the device being so arranged that regardless of the adjustments made, a coinplcte cycling of the flash welding machine always occurs.

A still further object of the invention is the provision of a hydraulic flash Welding control mechanism enabling a flash welding operation to start instantaneously and particularly with respect to the immediate movement of the movable platen of the flash welding machine.

A still further object oi the invention is the provision oi" a hydraulic flash welding control mechanism for a ash welding machine which will impart immediate and smooth action to the movable platen of the flash welding machine and continue such smooth progressive movement of the movable platen in accordance wtih a predete. lined flashing and upsetting cycle whether or not the movable platen dry or lubricated and regardless of the weight, shape, material or other' characteristics of the workpiece to the end that a pei-lect flash weld is obtained.

With the Aforegoing and other objects in View which will appear as the description proceeds, the inverr'on resides in the combination and arrange.-

of parts and in the details of construction ifiercifa'i'ter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen :for purposes 'of the disclosure, which do not consti-tute departures from the spirit and scope oi the invention.

e invention is illustrated in the accompanying drawing, wherein:

vFigure l is a schematic diagram of the hydraulic flash Welder control apparatus.

Figure is a top plan View of a portion of 'a'tus shown in Figure l.

lili-gu is a side elevation of the portion of the apparatus shot-1in in Figure 2.

Figure i is a horizontal section taken on line :ig-i of rieure Figure 5 is a side elevation of the portion of the apparatus shown in Figure 4 and taken on line '545 thereof.

'Figure G is an enlarged detailed elevation of a portion the apparatus shown in Figure l.

Figure "i is an enlarged detailed elevation of a portion of the apparatus shown in Figure 2.

Figure 8 is an enlarged detailed view of the portion of the tus shown in Figure 7.

By referring to 'the drawings and Figure l in particular it will be seen that a hydraulic flash Welder control is disclosed and that the same may be formed as a compact assembled unit including the control apparatus and the hydraulic fluid supply for the hash welding machine and that the complete hydraulic flash Welder control can be connected with any flash Welder to suitably operate the movable platen thereof to perform an improved flashing and upsetting welding cycle. Specifically, in Figure l of the drawings the nu nieral I indicates a tanl; which actually forms a supporting base for the remainder of the apparatus and provided with projecting feet ||-II so that the saine may be attached to a ilash welding machine or positioned in proximity thereto. The tank Iii comprises a reservoir for the hydraulic Huid utilized and a filter Ii is disposed in the tank I9 and connected with the outlet orifice I3 thereof which in turn is in direct communicaLA tion with a pump I4. The inlet orifice of the pump I4 is indicated by the numeral I5 and the outlet orifice is indicated by the numeral I5. rEhe pump I4 is driven 'ey an electric motor Il which is connected to the pump I4 by means of a coupling I8. A relief valve I3 having a pressure gauge 2) receives the hydraulic fluid from the pump I4 as the same is in communication with the outlet orifice IB of the pump I4.

A fluid supply line 2| connects with the relief valve I9 and with the controlling apparatus hereinafter described. The pressure relief Valve is arranged so that at such tin-ie as the flash welding machine inoperative, hydraulic fluid from the puni-p I4 is oy-passed Ithrough an oil cooler 22 which connected with the relief valve I9 by means of a tubular fitting 23 and with the tank l by means oi a tubular fitting 24.

At such time as a flash. welding machine controlled by the hydraulic flash Welder control disclosed herein is in operation, as, for example, a flashing and upsetting cycle, hydraulic fluid flows from the relief valve 'I9 through the fluid lsupply line 2| directly to an `accumulator 25 'which is preferably of the air bladder type and to a high pressure inlet port 26 on a flashing and upset control valve 2l. A check valve 23 is positioned in the fluid supply line 2| between the relief valve IS and the accumulator' 25 land permits fluid flow only toward the accumulator and the flashing and upset control valve 2'I.

Still lreferring to Figure l of the drawings 1t "ill be observed that the fluid supply line 2| includes a 'I' 29, a portion o'i which communicates by way of normally closed valve 38 with the tanl: I0 and which valve 3D is provided 'to `permit the accumulator to be drained. A second 'l' 3| in the fluid supply line 2| connects with a pressure reducing valve 32. A supply line 33 conveys hydraulic fluid at reduced pressure from the pressure reduc-lng valve 32 to two low pressuresupply lines 34 and 35 communicating respectively with a sequence starting valve 3S positioned above the flashing and upset control valve r2`I and with an upset pilot valve 3l which is disposed beneath the flashing and upset control valve 2l.

Positioned adjacent the sequence starting lvalve 3G there a flash control valve 38 including a recipro .lly positioned piston 39, an end--of which extends outwardly of tlieends of the flash control valve 38 and the left hand end of' which (as best illustrated in Figures 2 and 3 ol the drawings) is pivotally connected to a link 4I which in turn is pivotally connected to a cam arm 42. rilhe sequence starting vvalve 3G- and lthe :lash control valve 3S are integrally formed and shown inenlarged horizontal section in Figure 4 oi the drawings and in side elevation in Figure of lthcidraw ings. lt will be observed that ports A and Bin the sequence starting valve are in communication with ports A and B' in the `flashing yand upset control valve 2l which is shown in verticalsect-ion in Figures l. and 3 of the drawings and in cornnaunication with the upset pilot valve 3l which is directly connected thereto.

It will thus se seen that fluid pressurerom the pump Hand the accumulator 2-5 flows by way'of the fluidsupply line 2| directly to the inlet port 25 in the flashingand upset control valve 21 where it is controlled with respect to communication with a hydrauliccylinder 43. An outlet port 44 in the flashing and upset control valve 21 'is connected by ine-ans of a fluidsupply rline 45 with the closed'end of the hydraulicfcylinder 43. A piston 46 'is 'positioned withinthe cylinder 43 and a con necting rod 41 extends outwardly through the opposite end of the cylinder 43 and connects with a movable platen 48 of the welding apparatus. A return fluid line 49 establishes communication with the rod end of the cylinder 43 and with a port 50 in the flashing and upset control valve 21.

In Figures 2 and 3 of the drawings the cam arm 42 is shown connected with a cam 5I so that movement imparted to the cam arm 42 through the link 4l by the piston 4D in the flash control valve and piston 3B may be imparted to a spool 52 forming the multiple valve element in the flashing and upset control valve 21, as best illustrated in Figures l and 6 of the drawings.

Still referring to Figures 1 and 6 of the drawings it will be seen that the spool 52 is recprocally positioned in a sleeve 53 which in turn is reciprocally positioned in the body of the flashing and upset control valve 21. A plurality of slot-like ports are formed in the sleeve 53 for registry with a plurality of ports in the body of the valve 21 and more particularly with a hardened tubular insert positioned therein and defining the actual orillces, as hereinafter described. The spool 52 is spring urged toward the left as shown in Figures 1 and 8 of the drawings by a coil spring 54 positioned in the right hand end of the sleeve 53 and the outermost left hand end of the spool 52 is lprovided with a rotor 55 engaging the cam 5|. The right hand end of the sleeve 53, as shown in Figures 8, 2, 6 and 7 is connected with a bracket 56 which has a transversely extending slot 51.

A secondary bracket 58 is pivoted to the body of the flashing and upset control valve 21 by a pivot 59 and is normally disposed adjacent the bracket 56 and is provided with a transverse slot 60 in which a block 6| is slidably positioned. A rollei1 62 is pivotally mounted on the block 6| and is engaged in `the slot 51 in the .bracket 58. A threaded rod 58 is journaled at its ends in the bracket 58 and is provided with a crank 64 on one end. rThe threaded rod 83 passes through an internally threaded opening in the block 6| so that rotary motion imparted to the crank 64 results in travel of the block 6| and roller 52 longitudinally of the slots 51 and 6U.

A follow bar 55 which moves the secondary bracket 58 is slidably disposed beneath the body of the flashing and upset control valve 21 and is adapted to be engaged by a depending bracket 66 attached to one end of the spool 52 which is moved by the cam 5I. This is best illustrated in Figures 2 and G of the drawings. A screw 61 positioned through the depending bracket 86 is adapted to engage an abutment 68 on the follow bar 65 in an adjustable manner, the adjustment determining when relative motion between the spool 52 and the sleeve 53 starts. The secondary bracket 58 is normally urged toward the follow bar 65 by a coil spring 69 which is connected thereto and to one of the supports carrying the follow bar 85.

It will thus be seen that the bracket 56 on the sleeve 53 and the secondary bracket 58 posi tioned adjacent thereto are interconnected between the block 6| and the roller 62 to form a flashing curve control as the block 6| Iand the roller 62 comprise, in effect, a movable fulcrum for varying the relative motion of the sleeve 53 with respect to the motion of the spool 52. It will be seen that at such time as the roller 62 is moved to a point adjacent the pivot 59, the maximum motion of the spool 52 will be imparted by the follow bar 65 to the bracket 58 but that very little, if any, motion will be imparted to the bracket 58 by the interconnecting roller 62. On the contrary, at such time as the roller 62 is located in the slot 51 in spaced relation to the pivot 59, relatively greater motion will be imparted to the sleeve 53 thereby provid ing desirable variation in the flashing curve of the Welder controlled by the apparatus.

By referring now to Figure l of the drawings it will be seen that a composite view of the flash welding control apparatus is disclosed complete with interconnecting piping. The view includes a horizontal section through the flash control valve 38 and the appended sequence starting valve 36 and a vertical section through the flashing and upset control valve 21 and its appended upset pilot valve 31.

It is believed that from the foregoing one skilled in the art will observe that the flash welding control apparatus comprises essentially the flashing :and upset control valve 21 which directly controls the hydraulic fluid delivered by the pump I4 and the accumulator 25 to the platen moving piston and cylinder 46 and 43, respectively, the action of the flashing and upset control valve 21 being responsive to the operation of the piston 48 in the flash control valve 38, which is in turn responsive to the sequence starting valve 38 as hereinafter described. The movement of the piston 40 in the flash control valve 38 imparts predetermined movement to the cam 5I and hence the spool 52 of the flashing and upset control valve 21. Simultaneously with such movement of the spool 52, the motion of the cam 5l is imparted to the follow bar 65 and imparted thereby to the secondary lever 58 as heretofore described.

Assuming that the workpieces to be welded (not shown) have been secured in the stationary and movable platens of the flash welder control by the device and that the pump I4 is being operated by the motor I1 and hydraulic fluid is therefore being supplied the fluid supply lines 2|, 33, 34 and 35, the operating cycle of the flash welding machine is initiated by the manual or automatic closing of a switch 10. Closing the switch 10 closes the circuit in conductors 1l and energizes a solenoid 12 which moves a piston valve 13 in the sequence starting valve 36.

The piston valve 13 in the sequence starting valve 38 is normally biased to closed position by a coil spring 14 located adjacent one end of the piston valve 13. Motion of the solenoid 12 moves the piston valve 13 to the right, compresses the spring 14 and opens a fluid passageway from an inlet port 15 which is in communication with the hydraulic fluid supply line 34 and establishes communication with a pair of channels 16 and 11. The channel 16 comprises a by-pass channel and the channel 11 is under the control of a variable lloW control valve 18.

The channels 16 and 11 communicate with the right hand portion of the flash control valve 38, and responsive to the introduction of hydraulic fluid thereinto, the piston 40 in the flash control valve 38 will move to the left rapidly. The left end of the piston 48 is connected by means of the link 4I with the cam arm 42 heretofore referred to and the cam 5I is thus moved rapidly responsive to the rapid motion of the piston 40. Movement of the piston 40 causes an enlarged portion 19 thereof to close the channel 16, thus placing the flow control valve 18 in control of the amount of fluid delivered to the flash control valve 38 and hence controls the rate of travel of the piston 40 and hence the movement of the cam 5|.

The flow control valve 18 is a metering valve and, as may be seen by referring to Figure 2 of the drawings, is provided with a manually adjustable control lever BIJ by means of which the metering action of the flow control valve 18 may be controlled and preset. It will thus be seen that the sole function of the flash control valve 38 and its appended sequence starting valve 36 is to impart controlled mechanical motion to the cam which in turn moves the spool 52 and sleeve 53 of the flashing and upset control valve 21. The flashing and upset control valve 21 and its appended upset pilot valve 31 control the actual hydraulic iluid delivered to the cylinder 43 for actuating the piston 46 which is connected with the movable platen 48 of the dash Welder as heretofore described.

Still referring to Figure 1 of the drawings it will be seen that the fluid supply line 2| conveys hydraulic fluid to the inlet port 26 of the flashing and upset control valve 21 which communicates with an annular chamber 8| formed about the sleeve 53 by a cylindrical body member 82 which has spaced annular channels formed on its innermost surface and apertures communicating with said channels.

Hydraulic fluid introduced into the channel 8| (which comprises one of the annular channels in the cylindrical body member 82) thereby conipletely encircles the sleeve 53 and one or more apertures 83 in the sleeve are provided to convey the hydraulic fluid to the chamber Within the sleeve and between a pair of spaced tapered heads B4 and t5 on the spool 52. As the spool 52 is moved to the right by the cam 5I, as heretofore described, the head 85 will expose one or more orifices Si in the sleeve 53. The orifices 85 establish communication with an annular channel B1 in the cylindrical body member 82. The annular channel E1 is in communication with the outlet port `44 of the flashing and upset control valve 21. rI'he fluid supply line 45 con-- nests the outlet 44 with the closed end of the cylinder 43 so that hydraulic fluid is delivered to the cylinder 43 and moves the piston 45 and hence the movable platen 48 of the ash welding apparatus.

It will be observed that the head B5 on the spool 52 is provided with oppositely disposed tapers at different angles on its opposite so that a metering action is had with respect to the delivery of hydraulic fluid to the aperture 88 with the result that the movement imparted to the movable platen 48 is always smooth. It will also be seen that the position of the sleeve 53 meters the fluid delivered to the cylinder 43, and, the positions of the spool 52 and sleeve 53 are changing responsive to the flashing curve control of the block 9| and roller B2, a progressive llashing action results as the volume of iluid delivered to the cylinder 43 progressively increases.

Simultaneouly with the delivery of hydraulic iluid to the cylinder 43 and the movement of the platen 48 by the piston 46, as just described. the head B4 on the spool 52 moves to open an aperture t8 in the sleeve 53 which communicates with an annular chamber 89 in the cylindrical body member 52. The annular chamber 89 coin municates with the inlet port and the return fluid line 49 establishes communication between the inlet port 50 and the opposite end of the cylinder 43 sothat hydraulic iluid therein and being c charged therefrom through the return 'fluid ic fZG is gradually admitted to the chamber Within the sleeve 53 and to the left of the head B4 by the metering action of the tapered head 84. The hydraulic fluid thus admitted flows through one or more apertures in the sleeve 53 into an annular chamber 9| formed in the cylindrical body member 92 which communicates with an outlet port 92. A return line 93 establishes communication between the outlet port 92 and the tank |0 so that the hydraulic fluid is thus delivered thereto.

Still referring to Figure l of the drawings it will be observed that the piston 46 and the movable platen 48 will move to the right responsive to the admission of hydraulic fluid to the cylinder 43 under the predetermined control of the flashing and upset control valve 21, it being observed that the relative movement of the spool 52 carrying the heads 94 and 85 with respect to the sleeve 53 is controlled by the flashing curve control apparatus heretofore disclosed and described in connection with Figures 2 and 3 of the drawings whereby a desirable dashing curve or progressive motion of the movable platen 4b is achieved. The connecting rod 41 through which motion is imparted to the movable platen 4t is provided with a cani 94 which engages a switch 95 cci'itrolling` a circuit 9S. The circuit 96 is also connected with an upset solenoid 91 which is adapted to engage and move a piston valve 93 in the upset pilot valve 'S1 which is appended to the flashing and upset control valve 21.

Still referring to Figure l of the drawings the construction and operation of the upset pilot valve 31 may be seen. The solenoid 91 is directly connected with the piston valve 99 in the upset pilot valve 31. The piston valve 98 is normally biased to the right by a coil spring 99 in which position l and |0| block an inlet orice |02 which is in communication with the fluid supply line heretofore referred to, and hence with a source of hydraulic fluid from the pump I4, Operation oi the solenoid 91 moves the piston valve 93 to the left and establishes com munication between an inlet port |62 and an outlet port |03 which communicates with a channel |04 in the flashing and upset control valve 21 and whereby hydraulic duid is delivered to a chamber |05 in the flashing and upset control valve 21 adjacent a head |96 on the spool 52 so that the hydraulic fluid immediately moves the spool 52 and the sleeve 53 to the right accelerating the motion heretofore imparted thereto by the cam 5| (as heretofore described) and immediately fully opens the flashing and upset ports SS, B1 and 44 whereby a large volume ol hydraulic fluid delivered to the line 45 and the cylinder which results in an immediate upsetting' motion imparted to the platen 48 by the piston 4t responsive to the fluid action. Simultaneously with such action, the head 84 on the spool 52 is moved into fully open position with respect to the return line 49 and the inlet ports S, 89 and 88 so that hydraulic lluid on the opposite side of the piston 45 can be immediately delivered to the return line 93 and the supply tank l0.

It will occur to those skilled in the art that automatic timing devices can be incorporated in the controllingcircuits heretofore mentioned so that the period of energization of the solenoids 12 and 91, respectively, can be predetermined. At such time as the upset solenoid 91 is energized, the solenoid 12 controlling the sequence starting valve 36 is de-energized permitting the spring 14 to return the piston valve 13 therein to normal position at the left hand end of the sequence starting valve 36 and opening a communication line between the inlet port 15 and a fluid channel |01 which communicates with a chamber |08 in the flash control valve 38 and hydraulic fluid is thereby delivered to the left hand side of a head |09 on the piston 40 so as to move the same to the right thereby resetting the cam 5| for a subsequent welding operation.

After a suitable time interval, the solenoid 91 controlling the upset pilot valve 31 is deenergized and the spring 99 returns the valve piston 98 therein to normal position at the right hand end of the upset pilot valve 31 which closes communication between the inlet |02 and the outlet |03 thereof. Simultaneously, by-pass ports H and are placed in communication with a fluid channel I2 in the upset pilot valve 31. The fluid channel |2 communicates with an annular chamber I|3 in the ilashing and upset control valve 21 ,which in turn communicates by way of a port ||4 with a portion of the return line 93. It will thus be seen that hydraulic fluid in the chamber |05 is able to flow through the channels |04 and ||2 and the annular chamber H3 to the return line 93 and back to the tank I0. The spring 54 moves the spool 52 to the left to reset the valve for a subsequent welding operation and such action establishes communication between the inlet port 26 in the valve 21 with the annular chamber 8| about the cylindrical body member 82 and by way of the orifices S3 and 89 with the annular chamber 89 and the outlet port 59 so that hydraulic fluid then flows through the line 49 to the rod end of the cylinder 43 and thereby moves the piston 46 to the left to return the platen 48 to starting position for a subsequent welding operation. It will thus be seen that the flashing and upset cycle is completed automatically once the switch 10 is closed energizing the solenoid 12 which controls the sequence starting valve 36.

It will thus be seen that in a complete flashing and upset welding cycle flashing starts when the piston 40 moves to the left and moves the cam 5| through its interconnecting linkage which directly moves the spool 52 to the right and shortly thereafter imparts a relatively lesser degree of motion to the sleeve 53 by way of the follow bar 65 and the flashing curve control mechanism including the block 6| and roller 62 establishing variable fulcrum means between the follow bar 65 and the sleeve 53 with the result that the sleeve 53 moves to slowly open the orifices therein while the spool 52 opens the communication channels between the inlet port 26 and the orices with the result that the movable platen 48 moves in the flashing portion of the welding cycle.

It will occur to those skilled in the art that the speed of the movable platen 43 increases in accordance with the presetting of the flashing curve control 64, as heretofore described in connection with the block 6| and roller 52, so that a desirable completely variable flashing curve is achieved. It will also be noted that the action of the piston 40 in moving the cam 5| is initially rapid to eliminate delay in the start of the flashing cycle and subsequently is controlled by the flow control valve 18 which is also variable. As the relative motion between the spool 52 and the sleeve 53 progresses. the motion of 'the platen 48 increases as desired in the flashing cycle.

At such time as the cam 94 on the connecting rod 41 through which the movable platen 48 is moved reaches a predetermined upsetting point, the upsetting action is superimposed on the :lashing action with no hesitancy. This occurs by the energization of the solenoid 91 and its operation of the upset pilot valve 31 which immediately delivers fluid pressure to the chamber |05 in the valve 21 and instantly moves the spool 52 and sleeve 53 to the right to fully open the ilashing orifices in the sleeve with respect to the annular chambers in the cylindrical body member 82 and simultaneously moves the spool 52 to completely open the flashing ports. Full hydraulic pressure is thus instantly delivered to the cylinder 43 which results in the immediate upsetting action imparted the movable platen 48.

It will be obvious to those skilled in the art that a time delay mechanism may be incorporated if desired to control the length of time of the upset cycle. Alternately, the switch may be manually opened to permit the upset solenoid 91 to be de-energized. At such time as the upset solenoid 91 is energized, the starting sequence solenoid 12 is de-energzed either automatically or manually which thereby permits fluid pressure to reset the piston 40 and the cam 5|. Following the conclusion of the upset cycle, the de-energization of the upset solenoid 91 will permit the upset pilot valve 31 to reset and drain fluid from the valve 21 and thereby permit the spring 54 in the same to reset the spool 52 therein. Simultaneously, the spring 69 on the exterior of the device will reset the sleeve 53 and the complete apparatus is then ready for a subsequent welding operation.

It will thus occur to those skilled in the art that the complete hashing and upsetting cycle provided by the control apparatus occurs by reason of the relative movement of the spool 52 and the sleeve 53 in the valve 21 and that this relative movement is capable of being varied by the flashing curve control mechanism including the block 6| and roller 52 and the setting of the flow control valve 18. The only interconnection between the movable platen 48 and the apparatus is the cam 94 and the switch 95 controlling the upset solenoid 91. The time of operation of the switch 95 is dependent on the prior operation of the apparatus which is imparting controlled flashing cycle motion to the connecting rod 41 which carries the cam 94.

It will thus be seen that the several objects of the invention are met by the hydraulic flash Welder control disclosed herein.

Having thus described my invention, what I claim is:

l. Hydraulic control apparatus for a flash Welder having a normally fixed platen and a movable platen operated by a fluid pressure motor, said apparatus acting to control the movement of the movable platen during a welding cycle and comprising in combination a source of hydraulic fluid under pressure, a valve for controlling the flow of fluid from said source to said motor, said valve having two relatively movable valve elements, a secondary fluid pressure operated motor, variable motion transmitting mechanism interconnecting said secondary fluid pressure operated motor and said valve elements to move said valve elements relatively in such manner that the movement of the platen will follow a predetermined position-speed relationship during the flashing period of said cycle.

2. Apparatus according to claim 1 and further including a secondary metering valve controlling said secondary fluid pressure operated motor.

3. Apparatus according to claim 1 and further vll including a secondary metering valve controlling said secondary fluid pressure operated motor and a by-pass about said secondary metering valve positioned for communication with the said secondary fluid motor only during its initial movement.

4. Apparatus in accordance with claim 1 and wherein the variable motion transmitting means interconnecting the secondary fluid pressure operated motor and the valve elements includes a mechanical interconnection between the said iluid pressure operated motor and one of the said valve elements, the said mechanical interconnection including a fixed pivot and a sccondary pivot movable toward and away from said xed pivot to form a variable fulcrum with respect to the mechanical interconnection and the said valve element.

5. ln a hydraulic control for a flash Welder having a normally xed platen and a movable platen, means to control the movement of thc movable platen during the welding cycle com prising in combination a source of hydraulic iuid under pressure, a fluid pres-sure operated motor for moving said movable platen, valve means 'for controlling the iioiv of fluid from said source to said motor, said valve means having two relatively movable valve elements, a secondary fluid pressure operated motor, a solenoid valve in communication with said source of hydraulic fluid, said secondary iiuid pressure operated motor responsive in operation to opening of said solenoid valve, variable motion transmittine means interconnecting said secondary :fluid pressure operated motor and said valve elements to move the said valve elements in such manner that the movement of the platen will follow a predetermined position-speed relationship during the flashing period of said cycle.

6. In a hydraulic control for a flash Welder having a normally fixed platen and a movable platen, a source of hydraulic fluid under pressure, a iiuid pressure operated motor connected to said movable platen for movingT the same, a valve har-- ing two relatively movable elements for controlling the ow of iiuid from said source to said motor, a secondary uid motor, a secondary valve for metering the iiov.T of fluid from said source to said secondary motor, a cam adapted to be moved by said secondary motor and one oi said valve elements adapted to be moved directly by said cam, variable motion transmitting means interconnecting the other of the said valve elements and the said cam, the said means comprising' a mechanism having a fixed pivot and a secondary pivot movable toward and away from said fixed pivot to form a variable fulcrum with respect to the mechanism and the said valve element, the

arrangement being such that the said movable platen follows a. predetermined position-speed relationship during the flashing period 0I said cycle.

7. Hydraulic control apparatus for a 'Hash Welder having a normally xed platen and a movable platen operated by a uid pressure motor, said apparatus acting to impart desirable movcment to said movable platen and comprising in combination a source of hydraulic uid under pressure, a valve for controlling the flow of fluid from said source to said motor, .said valve having tivo relatively movable control elements, a servomotor, an arcuate cam pivotally mounted on said valve for rotation about its pivot, an arm interconnecting said cam and said servornotor so that the cam will be rotated thereby, said cam beine in engagement with one of said valve control clemente, mechanism connected to the other of said valve control elements including a fixed pivoi` and a. secondary pivot movable toward and away from said iixed pivot to form a 'variable fulcruni, said mechanism engaging said cam so that morement of said cam will result in a predetermined position speed relationship of said control elcinents of said valve, a secondary valve in comn munication with said iluid pressure source and with said valve means, said valve control elements responsive in opening movement to the opening' of said secondary valve to add a quick upsetting movement to the flashing cycle of said movable platen.

Apparatus according to claim l and further including valve control mechanism on said movable platen, said secondary valve responsive in operation to said valve control mechanism whereby the said upset movement imparted to the movable platen occurs by reason of predetermined movement of the said platen.

KINGSLEY A. DOUT'.

References Cited in the Ille of this patent UNITED STATES PATENTS Number' Name Date 718,973 Du Bois Jan. 27, 1903 939,792 Blumel Nov. lfCl 1,231,257 Herr June 1517 1,892,208 Ferris Deo. 27, i922 2,187,452 Gordon Jan. 1G, lill-i0 2,241,807 Cotner May 13, i941 2,274,224 Vickers Feb. 24, 1942 2,373,226 Coates Apr. 10, 194,5 2,455,526 Sciaky Dec. 7, 1948 2,516,449 Coates July 25, 1952 FOREIGN PATENTS Number Country Date 27,326 Great Britain of 1903 

